If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

We finally completed the nitrous install on my 335i. The power gains where phenomenal but as people know it is easy to get carried away. We found a medium result between boost and jet size and tuned the car to make 500whp at only 1 bar boost. We saw much higher numbers but at the moment until the gearbox is upgraded we will leave it at that. OB from Chip Logic work was meticulous both in terms of the wiring but also in terms of certain plumbing that was required to make the kit fit as best as possible. Below are some pictures with some explanations for those that are not familiar with nitrous.

The tank on the left provides fuel to the fuel nozzle without affecting the cars normal fuel pressure. A must for high horsepower application. The fuel line, nitrous line and wiring disconnect under the carpet. I can then lift the whole matt and replace it with a second one for grocery purposes.

The nitrous solenoids can be seen on the right corner of this picture.

This is the purge valve for the nitrous. The pipes for this was custom as we wanted the purge to come out at the fog lamp area.

Jet location with the jet in direct path of the intake manifold.
My methanol nozzle is also visible but is not in use at this stage.

The arming switch and purge switch, the rest is controlled by a progressive controller but we have installed as a extra safety measure a switch that allows the solenoids to active only if the overdrive button is pressed. That way I can go full throttle but only allow the progressive controller to do its thing when overdrive is pushed.

Other than that there is nothing visible in the interior.

The dyno printer was damaged but someone got a picture of one of our test runs in the early tuning stages, it also turned out the rpm was not set properly as the drop of point is 500rpm higher than it should be. Please keep in mind this was done at 5500ft. Base run on stock boost was 276whp and a average stock 335 makes under 250whp on this dyno. So the figures are comparitave to a Mustang dyno. No methanol was used for these numbers.

This is with a .40 nitrous and .23 fuel jet at 50psi fuel pressure controlled to 95% percent on the progressive controller. 5% more yielded another 20whp and but we decided to cap it at that till I get the transmission upgraded. The flash needed some fuel triming for a 500rpm range only and timing remained from 15 down to 11.

Originally Posted by Matt@Camber-Toe

damn 500whp at 14lbs and not stressing the engine with too much NOS is a sweet way to go

Is that fuel tank in the trunk entirely separate from the cars own fuel system? Meaning that once the NOS runs down you have to refill that tank?

Yes the fuel tank is totally separate, on a 15lb bottle of nitrous it has used a quarter of its capacity. Rule of thumb with that is just to fill it every time the bottle is changed because I haven't installed a fuel safety mechanism yet.

Originally Posted by blkclk550

How much did this set up run you parts and installation ?

Thank you.

The items from NX was US$2400. I did not pay for installation but it took us quite a bit of time as we never followed the NX wiring instructions and went our own route.

There's no crossing of torque and horsepower. HP and TQ cross at 5252 (always, its a math formula) so if yours are crossing out at 6200 RPM that means that every reading is wrong.

Quite a bold statement to make unfortunately . I think you jumped the gun on that one. Convert the torque of which is in nm to ft lb at 5250 and you will see the lines crosses with hp.
I am not out to get a dyno record or anything otherwise I would go post up dynos with 550's but that's not what the car produces the way its driven.

This is with a .40 nitrous and .23 fuel jet at 50psi fuel pressure controlled to 95% percent on the progressive controller. 5% more yielded another 20whp and but we decided to cap it at that till I get the transmission upgraded.

George,

You have a fuel distribution problem if you are seeing such a big jump from 95% to 100%. Basically, you are seeing an AFR as an average, not as a combustion event result, and you are having some events lean, and others are rich. It's the pulsing that's the issue.

FYI, I've done pulse testing on a wide range of solenoids, and I've never found the flow between the nitrous and fuel solenoids to be the same at X %. The WON solenoids are darn close, but it can vary a lot with other brands. Secondly, you will find the effective pulse range for solenoids to be between 15-85%....the latency is too great to go above this without some trickery which I can't talk about here.

Are you pulsing the fuel and nitrous solenoids on their own circuit with a delay between them?

You have a fuel distribution problem if you are seeing such a big jump from 95% to 100%. Basically, you are seeing an AFR as an average, not as a combustion event result, and you are having some events lean, and others are rich. It's the pulsing that's the issue.

FYI, I've done pulse testing on a wide range of solenoids, and I've never found the flow between the nitrous and fuel solenoids to be the same at X %. The WON solenoids are darn close, but it can vary a lot with other brands. Secondly, you will find the effective pulse range for solenoids to be between 15-85%....the latency is too great to go above this without some trickery which I can't talk about here.

Are you pulsing the fuel and nitrous solenoids on their own circuit with a delay between them?

Great to see someone using nitrous, and nice write up!

The solenoids are getting pulsed simultaneous from the progressive controller. We moving to a slightly smaller jet keeping the same jet with the slight increase in power and having the solenoid staying open for the lions share of the rpm range. I am not a big fan of pulsing the solenoids longer than should. They are tricky and you are right in saying the results are always not the same. The possibility of the great gain on the last five percent which is actually six as its at 94% might also be the result from slight boost creap as the run where back to back so the ECU had no chance to learn the boost ramp curve.

The solenoids are getting pulsed simultaneous from the progressive controller. We moving to a slightly smaller jet keeping the same jet with the slight increase in power and having the solenoid staying open for the lions share of the rpm range. I am not a big fan of pulsing the solenoids longer than should. They are tricky and you are right in saying the results are always not the same. The possibility of the great gain on the last five percent which is actually six as its at 94% might also be the result from slight boost creap as the run where back to back so the ECU had no chance to learn the boost ramp curve.

George,

You are doing a lot of things right, like the dedicated fuel cell and running a higher fuel pressure. (50psi vs the 5-10 psi that some chose to run)

You probably already know this, but it's the fuel that makes the power, not the nitrous, and your currently fueled for 68 hp. You are seeing more because of the obscene amount of intercooling that nitrous provides, which is a great thing, but you have a good handle on being careful from the sounds of it.

One thing that's missing from your dyno graph is the AFR plot, specifically what happens when the nitrous system is activated. Do you have a lean spike? If so, how long does it last? I've used either a 2 stage controller with nitrous and fuel hooked up to different stages to "time" the activation point, and get rid of the lean spike electronically. The best scenario though is to put the fuel solenoid within inches of the discharge nozzle. I've played with running 8", 12", 18", and 24" nitrous lines after the nitrous solenoid, and found that the difference in activation delay was minimal, and that you get a lot better effect by keeping the fuel solenoid closer to the discharge nozzle. I personally prefer to "fix" an activation lean spike physically, rather than electronically.....

Unless you are running WON solenoids, you are smart to steer away from pulsing, and get the jetting right. FYI, I've been pulsing WON solenoids @ 50hz with great results....you are probably stuck pulsing the NX pieces under 20hz, which isn't as smooth. (I own those same solenoids, and they aren't bad...just not designed to be pulsed)

You are doing a lot of things right, like the dedicated fuel cell and running a higher fuel pressure. (50psi vs the 5-10 psi that some chose to run)

You probably already know this, but it's the fuel that makes the power, not the nitrous, and your currently fueled for 68 hp. You are seeing more because of the obscene amount of intercooling that nitrous provides, which is a great thing, but you have a good handle on being careful from the sounds of it.

One thing that's missing from your dyno graph is the AFR plot, specifically what happens when the nitrous system is activated. Do you have a lean spike? If so, how long does it last? I've used either a 2 stage controller with nitrous and fuel hooked up to different stages to "time" the activation point, and get rid of the lean spike electronically. The best scenario though is to put the fuel solenoid within inches of the discharge nozzle. I've played with running 8", 12", 18", and 24" nitrous lines after the nitrous solenoid, and found that the difference in activation delay was minimal, and that you get a lot better effect by keeping the fuel solenoid closer to the discharge nozzle. I personally prefer to "fix" an activation lean spike physically, rather than electronically.....

Unless you are running WON solenoids, you are smart to steer away from pulsing, and get the jetting right. FYI, I've been pulsing WON solenoids @ 50hz with great results....you are probably stuck pulsing the NX pieces under 20hz, which isn't as smooth. (I own those same solenoids, and they aren't bad...just not designed to be pulsed)

What controller are you running?

At the moment in terms of fueling we in the safe level of what the stock system can give extra. At higher boost level we will have to go with a minimum .28 fuel jet. The spike you mention is evident and takes the initial AFR to 14's for around 200rpm. We avoiding purging at this stage to avoid this but its not really a train smash in my opinion. When I get the upgraded gearbox I will be going direct port and we will use the 2 stage method you mentioned through the NX controller. The extending of the nitrous line is also affective but we do not have the luxury of having a shop around the corner here in South Africa. Chances are the nitrous solenoid will stay in the existing place and the fuel solenoid will be close to the manifold.
Thank you very much for the effort you have taken to put down your experience for every ones benefit. I am going to look at the WON solenoids and test out a set.

Great information George! When are you headed to the track and will you be running meth while there?

Our next track day is on the 4th of September. Will be doing some testing to see if there is any benefit of using the methanol until then and if the gearbox arrives in time will be going with bigger jets. Lets see what happens. I do not expect to duplicate US numbers here but from what I have seen I stand a good chance of getting the 60-130 record even at this altitude.